Robots have been increasingly used in manufacturing operations to move tools and workpieces. Especially during the set-up operation of the robot, the tool or workpiece is apt to strike some other part of the machinery. This can shear pins or fasteners before the robot can be stopped.
A number of prior patents have dealt with the problem of limiting the force, such as U.S. Pat. No. 3,145,333. U.S. Pat. No. 4,016,803 has suggested use of a servomotor in a robot with a throttled stop of the robot. Other patents have suggested the use of a movable probe to control an electrical transducer to sense the movement of the probe, as in U.S. Pat. No. 4,328,621. U.S. Pat. No. 4,442,754 suggests the use of a compound slide in a fluid-powered positioning system for a robot.
The present invention is a mechanism to detect overload in a robot and to protect a robotic end-of-arm tooling in the event the robot accidentally strikes an object in its path while moving from one point to another. This feature may be of particular significance during initial robot programming when the arm is moving at reduced speed and can halt movement in a short distance after the collision is detected and an electrical signal is sent to the robot control.